Some data centers are equipped with a plurality of blade chassis (hereinafter, referred to as chassis) including devices shared by blades, such as a power source unit and a cooling fan. To reduce power consumption, such data centers integrate virtual machine (VM) guests that operate on a blade in a certain chassis into another chassis to turn off the power of the certain chassis, for example. Besides for reduction in power consumption, such data centers turn off the power of a chassis for maintenance of the chassis, for example.
To turn off the power of a chassis, first VM hosts, such as a blade server and a rack server, mounted on the chassis determine a destination of VM guests that operate on the first VM hosts from second VM hosts mounted on another chassis. The first VM hosts then move the VM guests to the destination thus determined. After moving all the VM guests that operate on the first VM hosts to any of the second VM hosts, the first VM hosts turn off the power thereof. Subsequently, the chassis checks that the power of all the VM hosts mounted on the chassis is turned off with management software, for example. The chassis then turns off the power thereof. Some conventional examples are described in Japanese Laid-open Patent Publication No. 2011-039906 and Japanese Laid-open Patent Publication No. 2007-323244.
The conventional technologies, however, may possibly fail to turn off the power of the chassis, thereby failing to reduce power consumption. This problem is not limited to the chassis. Also when turning off the power of physical servers, such as a rack server and a tower server, in which the VM hosts operate to reduce power consumption, the conventional technologies may possibly fail to turn off the power of the physical servers, thereby failing to reduce power consumption.
A VM host in such a data center, for example, is assigned VM hosts serving as destination candidates to which VM guests of the VM host can be moved by an administrator or the like. To move the VM guests, the VM host moves the VM guests to a VM host mounted on a chassis whose power is on among the destination candidates, for example. The VM host then turns off the power thereof.
If there is no other destination of a VM guest that operates on another VM host than the VM host whose power is turned off, the VM host may possibly be specified as the destination. As a result, the chassis fails to turn off the power thereof.